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Abstract

Women with Turner syndrome (TS) have an increased risk of congenital cardiovascular defects. Previous studies have reported a 10 –20% prevalence rate of bicuspid aortic valves and there are increasing reports of a vasculopathy that predisposes patients to aortic dilatation and dissection. This prospective study aimed to characterize aortic valve and aortic root structure in unselected asymptomatic individuals with TS. A total of 253 females aged 7– 67 years with karyotype proven TS were examined. Transthoracic echocardiography revealed a normal tricuspid aortic valve (TAV) in 162, a ‘probable TAV’ in 8 subjects, a bicuspid aortic valve (BAV) in 65 and ‘probable BAV’ in 3 subjects. The aortic valve could not be visualized by echocardiography in 15/253 or 6%. Magnetic resonance imaging (MRI) revealed valve structure in 11/12 of the probable cases (all confirmatory of the ‘probable’ diagnosis) and 12/15 of the non-visualized cases (8 BAV and 4 TAV), so only 3/253 subjects could not be visualized by either modality. The aortic valve was bicuspid in 76 of the 250 adequately imaged subjects (30%). Peak aortic valve flow was higher in BAV subjects (1.72±0.07 vs. 1.90v0.03 m/sec, P=0.0002), with one case of significant aortic stenosis. Among subjects with a BAV, aortic regurgitation was moderate or greater in ∼15%. Aortic diameters at the annulus, sinuses of Valsalva, sinotubular junction and ascending aorta were all significantly greater in the BAV group. Thirty patients in the BAV group (12%) had aortic root diameters that were outside of the 95% normal confidence limits based on Roman nomograms. Ascending aortic diameters by echo and MRI were highly correlated (r=0.77). In summary, echocardiography supplemented with MRI reveals an extraordinarily high prevalence of abnormal aortic valves in asymptomatic subjects with TS. The abnormal valve structure is associated with higher peak flows, evidence of clinically significant valvular dysfunction, and widening of the ascending aorta in a significant number of patients. All girls and women with TS should have careful echocardiographic evaluation upon diagnosis to identify the one in three asymptomatic individuals with an abnormal valve requiring monitoring for aortic root dilatation and valvular dysfunction.